Apparatus for producing fibers from thermoplastic material



1966 M. LEVECQUE ETAL 3,235,722

APPARATUS FOR PRODUCING FIBERS FROM THERMOPLASTIC MATERIAL Original Filed Feb. 21, 1956 Flwilll I II II II II El 2| II II :I

INVENTORS M43664 ZEVECQr/E Mazda; Mfla/fu Mane/c5 cwmepswr/eze ATTORNEY other, for example 2 to 20 rows. "ed from the centrifugal body are subjected to the action of United States Patent 3 285 722 APPARATUS FOR PEKOD UCING FIBERS FRUM THERMOPLASTIC MATERIAL .Marcel Levecque, Saint-Gratein, Marcel Mabru, Paris, and

Maurice Charpentier, Rantigny, France, assignors to Compagnie de 'Saint-Goba'in, Paris, France, a corporation of France Original application Feb. 21, 1956, Ser. No. 567,023, new

Patent No. 3,114,618. Divided and this application Oct. 25, 1963,Ser. No. 318,857

Claims priority, application France, Feb. 28, 1955,

8 Claims. c1. 65-15) This application is a division of our application Serial No. 567,023, filed February 21, 1956, now Patent Number 3,114,618.

The present invention relates to the manufacture of fibers of mineral materials in the viscous state and particularly glass fibers.

"the hollow body being surrounded by a combustion chamber taking the shape of an annular crown whose expansion orifice in the form of a continuous slot or a series ofholes projects a ring-like blast of hot gases perpendicular to the plane of projection of the filaments from the orifices. A structure of this general type is shown in United States patent to Pierre Rene Heymes and Ivan Peyches No. 2,624,912, issued January 13, 1953. The described procedure and arrangement allows for an efficacious drawing out of the filaments as soon as they leave the orifices, these filaments being drawn out and carried along withgreat force by the combustion gas escaping from the expansion orifice to form the fine fibers. However, because of the limited number of orifices provided on the peripheral edge of the rotating body, the fiber production of these arrangements is relatively low.

The present invention has for an object an improvement to the process and the arrangements noted above Conforming to the invention, the pla tic material is projected at high temperature from a centrifugal body "or element whose peripheral or filamefit delivery part, which can be notably of a cylindrical shape, bears a certain number of rows of projection orifices, one above the The filaments projectand permits a large and substantially nQ/prm production 'fine fibers. One might fear that the fact of providing two or more rows of projection orifices on the periphery of the centrifugal body might lead the fibers issuing from these orifices to stick and hinder the drawing out. Applicants have found that by distributing the projection orifices into several rows on the peripheral wall of the centrifugal body there is obtained a simultaneous drawing of the glass projected from these orifices, even if the I orifices-are lined up in the direction of the gas current.

3,285,722 Patented Nov. 15, 1966 It has been possible, in fact, to observe exactly the different individual paths formed by the melted material projected from each orifice of the several rows of orifices.

Applicants have also found that the fibers thus formed can be drawn below the centrifugal body but may have a tendency to regroup in the still plastic or hot state. This can result notably when the centrifugal body is surrounded by a combustion chamber having as expansion orifices, a continuous slot, or holes or slots very close together. In these circumstances there is formed below the centrifugal body a turbulent motion of air or gases which create a low pressure zone below the centrifugal body with a tendency to carry into that zone the hot gases from the combustion chamber and hence the fibers entrained therein. This phenomenon can cause several serious drawbacks, especially the sticking of fibers under the centrifugal body and a sticking together of the regrouped fibers and possibly collecting deformed filaments appearing as rigid and breaking small rods. These deficiencies are more noticeable as the number of orifices in the centrifugal body are increased and production of fibers enlarged.

One of the objects of the present invention is to correct the above deficiencies, and provision is made for the direction of the fiber entraining and drawing gaseous currents issuing from the combustion chamber in such a Way as to restrain their movement toward the axis of the cen trifugal body or even cause their movement away from said axis after the gaseous currents come into contact with and entrain the filaments projected by the centrifuging body. This guidance of or control over the gaseous currents issuing from the combustion chamber may be effected by the use of air or gas currents or mechanical deflection elements located below the centrifugal body.

According to one form of the present invention, a space or spaces are provided between the orifices for the escaping combustion gases which enables air from the surrounding atmosphere to enter the inside of the ring formed by the hot gases. These orifices can be made up of a certain number of slots appropriately spaced one from the other and surrounding the centrifugal body or they can be made up of circular orifices appropriately spaced. This introduction of air avoids the premature regrouping of the fibers below the centrifugal body and at the same time imposes a directional influence upon the evacuation of the fibers drawn by the hot gases.

It is also possible to regulate or control the direction of the currents of hot gases as they escape the annular combustion chamber. For this purpose, the orifices are divided into two or more groups, the gas currents of each group making a small angle with those of the other groups. Under these conditions a mutual induction effect is produced which gives directional stability to the resulting gas current and prevents its convergence below the centrifugal body with its entrained fibers.

The invention also provides for the guiding of the hot gas currents issuing from the combustion chamber by means of suitably streamlined surfaces. These surfaces may be integral with the centrifugal body. For example, the peripheral surface containing the orifices in the centrifugal body can be in the form of a truncated cone, and in this way, itself cause the deflection of the hot gas currents brought into contact with it, and consequently of the fibers entrained therein.

The drawings illustrate preferred embodiments of the invention wherein:

FIG. 1 is a side view partly in section showing the centrifugal body surrounded by the combustion chamber with its expansion orifices in position to deliver hot gases downwardly to entrain and draw out the filaments projected from the centrifugal body;

FIG. 2 is a bottom plan view of the centrifugal body and the combustion chamber showing spaced expansion and delivery slots in the latter;

FIG. 3 is a fragmentary vertical section through the centrifugal body and the combustion chamber illustrating the difference in angle of a group of expansion and delivery slots for the hot gases with another group of slots; and

FIG. 4 is a fragmentary vertical section through a centrifugal body having its peripheral surface in the form of a truncated cone with the walls of the expansion and delivery orifices of the combustion chamber inclined to approximate or equal the inclination of the frusto-conical surface of the centrifugal body.

In the illustrated embodiments of the invention, a centrifugal body 1, rotating at high speed about its axis, through appropriate driving means at a speed of 3000 revolutions per minute or higher, carries at its peripheral part a cylindrical wall 1b bearing two to twenty rows of projection orifices 2 of suitable diameter, through which the molten material is projected at a temperature of about 1300 C.

It is advantageous for the orifices provided in the frontal peripheral wall of the centrifugal body to be separated in such a way that the distances separating the neighboring orifices be about the same. A suitable spacing of the orifices can be made by placing them according to regular quincuncial arrangements. A combustion chamber 3 of general annular shape is provided with an expansion orifice or orifices 4 which delivers the combustion gas at a very high speed and high temperature. The orifice 4 and the wall or walls defining the same are so positioned in respect to the peripheral wall 1b of the centrifugal body and the orifices contained therein that the molten material or filaments as they are projected from the centrifugal body or at a slight distance therefrom are thrown into and picked up, entrained in and drawn by the hot gases passing across the peripheral surface of the centrifuge wall 1b and at an angle to the normal line of projection of the filaments from the centrifugal body. In FIG. 1, this angle would be approximately 90; in FIG. 4 the angle shown is approximately 45 although a smaller angle is preferred. These hot gases pass lightly over the peripheral wall of the centrifugal body and are in contact with all the projection orifices.

In the embodiment shown in FIGS. 1 and 2, the expansion orifices are made of a certain number of spaced slots 4a, 4b, 4c, 4d, 4e, 4 By way of example, these slots may be six in number and separated by an interval of their length. This spacing of the slots and the hot gases or blasts issuing therefrom affords room for the entrance of outside air to the interior of the segmental ring of hot gases (see dotted arrows A, FIG. 2), thus retarding or arresting the turbulent motion of air or gases and the low pressure zone heretofore referred to.

In the form of the invention illustrated in FIG. 3, the slots of the combustion chamber discharging the hot gases are divided in effect into a series of slots, the angle of one slot varying with the angle of the next adjacent slot and so continued throughout the annular series. Or they may be divided into two or more alternating groups 44', the gas currents of each group making a small alpha angle with those of the other group or groups. By way of example, the angle of the two currents should preferably be less than 20. This arrangement produces a mutual induction effect giving directional stability to the resulting hot gas current as heretofore described.

In the form of the invention illustrated in FIG. 4, the peripheral wall carrying the projection orifices is a truncated cone, its generatrix forming with the axis of the centrifugal body a beta angle less than 45 and in particular an angle of 20. According to this embodiment, the gas jets are themselves advantageously inclined on the axis of the centrifugal body forming with it an angle near the beta angle, This arrangement serves to direct the hot gases and entrained fibers outwardly and thus prevents the hot gases with the entrained fibers from converging inwardly toward the axis of the centrifugal body where the fibers might regroup or stick together while still plastic.

In all forms of the invention, the centrifugal body and its upwardly extending tube 10, FIG. 1, will be heated internally by an appropriate burner or burners (not shown) so as to maintain the molten supply of material passing through the tube and into the interior of the centrifuge in a homogeneous state and at the proper centrifuging temperature.

Likewise in all forms of the invention, the fibers projected from the orifices in the centrifugal body enter but do not pass through or beyond the hot gases issuing from the combustion chamber. Once the fibers enter the ring of hot gases or are picked up by those gases they are entrained therein and turned downwardly and attenuated and drawn into fine fibers by the travel and traction exerted by those gases. This end will be attained by appropriately adjusting or regulating the centrifugal force and the force of the hot gases issuing from the hot chamber.

We claim:

1. In apparatus for producing glass fibers from thermoplastic vitreous material, the combination of a centrifugal body having a peripheral wall provided with a plurality of superposed rows of orifices therein and adapted to receive at its interior portion a supply of the thermoplastic material in the viscous state, said body being rotatable at a speed sufiicient to project the viscous material outwardly and uniformly through said orifices in the form of streamlets, a combustion chamber surrounding said body and provided with discharge means having walls shaped to direct the discharge of gases from said chamber at high temperature and high velocity in a ring-like blast across said rows of orifices close to and in light contact with the peripheral wall of said body, said gases travelling transversely to the planes of projection of said streamlets whereby said streamlets of viscous material issuing from the orifices of the rotating body are turned, entrained and drawn out into an annular curtain of fine fibers by said gases, and means for controlling said discharge means in said combustion chamber relative to said peripheral wall to divert said annular curtain of fine fibers subsequent to their formation and initial attenuation from below said centrifugal body.

2. An apparatus as set forth in claim 1 wherein the peripheral wall of said centrifugal body is of frusto-conical formation diverging outwardly below said combustion chamber, and the discharge means in said chamber comprises walls shaped to form a passage adapted to direct the gases issuing from said chamber along a frusto-conical plane substantially parallel to the plane of said peripheral wall, so that the annular curtain of fine fibers is diverted outwardly from below the centrifugal body.

3. In apparatus for producing glass fibers from thermoplastic vitreous material, the combination of a centrifugal body having a peripheral Wall provided with a plurality of superposed rows of orifices therein and adapted to receive at its interior portion a supply of the thermoplastic material in the viscous state, said body being rotatable at a speed sufficient to project the viscous material outward and uniformly through said orifices in the form of fibers, a combustion chamber located adjacent said body and provided with a plurality of segmental discharge openings spaced from each other, each of said openings having walls shaped to direct the discharging spaced streams of gases from said chamber at high temperature and high velocity in a ring-like blast across said rows of orifices transversely to the planes of projection of said fibers whereby said fibers of viscous material projected from the orifices of the rotating body are turned, entrained in and drawn out by said gases.

4. An apparatus as set forth in claim 3 wherein the gaps between the segmental discharge openings approximate one-fifth of the length of the latter, through which air is admitted from the outside of the ring-like blast of gases to the interior thereof.

5. An apparatus as set forth in claim 3 wherein the walls of at least some of the segmental discharge openings are shaped to sweep the periphery of the centrifugal body in a direction normal to the planes of projection of the fibers.

6. An apparatus as set forth in claim 5 wherein said segmental openings with walls shaped to sweep the periphery of the centrifugal body in a normal direction alternate with segmental openings having walls shaped to sweep the periphery of the centrifugal body divergently relative to the rotary axis of the centrifugal body.

7. In apparatus for producing glass fibers from thermoplastic vitreous material, the combination of a centrifugal body having a peripheral wall provided with a plurality of superposed rows of orifices therein and adapted to receive at its interior portion a supply of the thermoplastic material in a viscous state, said body being rotatable at a speed sufiicient to project the viscous material outwardly and uniformly through said orifices in the form of streamlets, a combustion chamber surrounding said body and provided with discharge means having walls shaped to direct the discharge of gases from said chamber at high temperature and high velocity in a ring-like blast across said rows of orifices close to and in light contact with the peripheral wall of said body, said gases travelling transversely to the planes of projection of said streamlets whereby said streamlets of viscous material issuing from the orifices of the rotating body are turned, entrained and drawn out into an annular curtain of fine fibers by said gases, the peripheral wall of the centrifugal body having a frusto-conical shape so as to control the direction of discharge of said ring-like blast of gases to divert said annular curtain of fine fibers subsequent to their formation and initial attenuation from below said centrifugal body.

8. In apparatus for producing glass fibers from thermoplastic vitreous material, the combination of a centrifugal body having a peripheral wall provided with a plurality of superposed rows of orifices therein and adapted to receive at its interior portion a supply of the thermoplastic material in the viscous state, said body being rotatable at a speed sufiicient to project the viscous material outward and uniformly through said orifices in the form of fibers, a combustion chamber located adjacent said body and provided with a plurality of segmental discharge openings, each of said openings having walls shaped to direct the discharging spaced streams of gases from said chamber at high temperature and high velocity in a ringlike blast across said rows of orifices transversely to the planes of projection of said fibers whereby said fibers of viscous material projected from the orifices of the rotating body are turned, entrained in and drawn out by said gases, the walls of at least some of the segmental discharge openings being shaped to sweep the periphery of the centrifugal body in a direction normal to the planes of projection of the fibers and alternating with segmental openings having walls shaped to sweep the periphery of the centrifugal body divergently relative to the rotary axis of the centrifugal body.

References Cited by the Examiner UNITED STATES PATENTS Re. 24,708 9/1959 Haymes et al -6 2,609,566 9/1952 Slayter et al 65-14 X 2,931,422 4/1960 Long 182.5 X

FOREIGN PATENTS 1,124,489 2/ 1955 France.

DONALL H. SYLVESTER, Primary Examiner.

R. L. LINDSAY, Assistant Examiner. 

1. IN APPARATUS FOR PRODUCING GLASS FIBERS FROM THERMOPLASTIC VITREOUS MATERIAL, THE COMBINATION OF CENTRIFUGAL BODY HAVING A PERPHERAL WALL PROVIDED WITH A PLURALITY OF SUPERPOSED ROWS OF ORIFICES THEREIN AND ADAPTED TO RECEIVE AT ITS INTERIOR PORTION A SUPPLY OF THE THERMOPLASTIC MATERIAL IN THE VISCOUS STATE, SAID BODY BEING ROTATABLE AT A SPEED SUFFICIENT TO PROJECT THE VISCOUS MATERIAL OUTWARDLY AND UNIFORMLY THROUGH SAID ORIFICES IN THE FORM OF STREAMLETS, A COMBUSTION CHAMBER SURROUNDING SAID BODY AND PROVIDED WITH DISCHARGE MEANS HAVING WALLS SHAPED TO DIRECT THE DISCHARGE OF GASESS FROM THE CHAMBER AT HIGH TEMPERATURE AND HIGH VELOCITY IN A RING-LIKE BLAST 